(01-21-2017 03:00 PM)Owl 69/70/75 Wrote:  

(01-21-2017 01:36 PM)RiceLad15 Wrote:  As others pointed out, the biggest issue with renewables is the inability at the moment to provide a good base load on a consistent basis.

Actually, the biggest flaw with renewables is their inability to power mobile applications, like cars.

To parse, you need to differentiate between energy uses --- whether they require high density or low density. You really cant lump everything into one basket.

For transportation --- you absolutely require high density solutions. Even low energy density motors (think Tesla) need very high density bundles associated with them to make them usable. The battery is the *only* device that transforms really low energy density (straight current) into anything approaching a high density package. Even then, you are payload restricted. This is why even with motorization you will see small discrete things that move (cars, carts, mopeds). There is not presently any way to make a parcel that will move a semi or a freighter with any efficacy approaching motors utilizing high energy density sources (i.e hydrocarbon based),

Similar arguments can be used to show that high energy industrial applications (cement, steel, etc.) cannot be done effectively with low density energy sources (i.e. electric, no matter ists source).

Looking at the other side, there are applications that really only require low energy density power sources (electricity being the best example). One way of producing this low energy density power is to transform high energy density sources (coal, uranium, gas) into low energy dense forms through the generation process. But greens do a decent job at capturing low density energy forms and transforming them into electricity. Its just that the methodologies arent anywhere near as constant and dependable as opposed to "downgrading" high energy density forms to electricity.

But cars can definitely be powered by renewables -- electric cars are becoming more and more normalized; albeit performance will lag as defined by the source density issue. Another 'renewable' is bio-diesel -- albeit with a high necessity of added energy (or time) to produce. Yet another is fuels made from high cellulose based plants -- think switchgrass fuels made in Brazil. Again, one has to add some energy to make this step, and that energy can be in the form of added high density production methods, of low density usage integrated over longer periods of time.

So I think cars is very doable. Big scale stuff like freighters and semis are more problematic with direct low density energy usage. One can make fuels for these, but need added energy which means long term density usage in production over a short time or low density usage in production over much, much longer times.

Quote:To refer to your analogy in the part I didn't quote, neither the mobile problem nor the base load problem nor the scale and infrastructure problems (which we really haven't gotten to yet because we are not that far along the development curve) are specks. They're more like massive boulders. Or maybe mountains.

We need to transition from non-renewable energy sources to renewables. But before we can transition, we need something to transition to. That's still missing at this point.

Apologies for the long winded reply; first job out of Rice was in the oil industry, and have had my toe in various energy related fields for a long time now.